Most Popular Extensions
Enigmail Requires Restart Featured
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.
Mozilla Archive Format, with MHT and Faithful Save Requires Restart
— Open web pages saved with Internet Explorer or other browsers (MHT)
— Save many tabs, video and audio reliably, in a single ZIP file (MAFF)
— Return to the original site you saved a page from, and more!
Image Zoom Requires Restart
Adds zoom and rotation functionality for images...
Lucifox Requires Restart
Read EPUB e-books and browse OPDS catalogs.
Live HTTP Headers Requires Restart
View HTTP headers of a page and while browsing.
Proxy Tool Requires Restart
Proxy Tool - Powerful, yet User-friendly proxy tool to manage your proxies and anonymity needs, including: 46M+ user agents (world's largest), 10 different spoofed HTTP referrers, auto-proxy rotation, plus many more. Developed by http://ProxyList.co
Screengrab (fix version) Requires Restart
Screengrab! saves webpages as images.
New features: upload to internet
ChatZilla Requires Restart
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
Youtube MP3 Podcaster Requires Restart
Self contained add-on for downloading youtube videos to mp3 for easy listening on podcasting gadgets like a Zune or iPod
DOM Inspector Requires Restart
DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM can be navigated using a two-paned window displaying a variety of different views on the document and all nodes within.
Now with 1080p Full-HD Support!
Download every YouTube video you want and you can download them as Full-HD MP4, FLV, 3GP, MP3, M4A and AAC formats. Easy & Fast!
Get a faster browsing experience by blocking nasty web resources using Bluhell Firewall, the lightweight Ad-Blocker and Tracking/Privacy Protector.
Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.
Thumbnail Zoom Plus Requires Restart
Shows full image when you hover over a thumbnail. Works with Amazon, Baidu Images, Bing Images, Facebook, Flickr, Google+, Google Images, IMDb, LinkedIn, Netflix, Pinterest, Reddit, Twitter, Yandex, YouTube, Wikipedia, Yahoo Images, & many more.
As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.
Theme Font & Size Changer lets you change the global font size and font family used for the user interface in Firefox. Design your browser with your favorite font.
UnMHT allows you to view MHT (MHTML) web archive format files, and save complete web pages, including text and graphics, into a single MHT file in Firefox/SeaMonkey.
Ad-Aware Ad Block improves your browser’s speed and protects your privacy by blocking ads and trackers. It also improves online security by blocking malicious URLs and establishing the most secure connection available.
Saved Password Editor Requires Restart
Adds the ability to create and edit entries in the password manager.